1. Field of the Invention
The present invention relates to a light guide plate for use in a liquid crystal display. In particular, the invention relates to a light guide plate for use in a liquid crystal display that has a sidelight emission type of backlight module.
2. Descriptions of the Related Art
LCDs (Liquid crystal displays) are lightweight and thin. Today, LCDs are greatly substituted for CRT (cathode ray tube) monitors.
Because the liquid crystal panels of the LCDs are not self-illuminant, lights need to be supplied by a backlight module. These lights can partially penetrate through the liquid crystal panel to form images. In addition, voltages are needed for the liquid crystal panel to twist or tilt the liquid crystals. Consequently, the backlight module serves as the illuminant element in the LCD. The light quality of the backlight module, which is associated with the property of the tilted liquid crystals in the liquid crystal panel and the appropriate control of switch elements, determine brightness, performance uniformity and image quality of the LCDs.
Presently, the backlight modules of side light emission type are widely applied in LCD TVs, desktop LCD monitors, LCD display on mobile phones and so on. This particular type of backlight modules comprises a light guide plate and a light source. The light incidence face of the light guide plate is substantially perpendicular to the light emission face of the light guide plate. The light source is disposed adjacent to the light incidence face. When the lights are guided into the light incidence face, the lights are then reflected onto the light emission face with the guidance of the light guide plate. Subsequently, the lights that are emitted out from the light emission face are provided onto the liquid crystal panel which is disposed above the backlight module. The aforesaid light source is, but not limited to, an LED (light emitting diode), a fluorescent lamp, or a cold cathode fluorescent lamp.
Unfortunately, indispensable total reflections occur when the lights initially travel through the light guide plate. The total reflections of the light guide plate delay the lights from emitting out of the light emission face, causing inferior brightness and uniformity levels of light output. To remedy the situation, it is necessary to reinforce the brightness and uniformity of the light supplier, i.e. the backlight module, by additionally providing an optical sheet, or by modifying the design of the light guide plate. However, the existing measures of improvement increase complexity in the manufacturing and assembly of the product.
Given the above complications, there is a need to develop a novel light guide plate, a backlight module and a liquid crystal display comprising the same.